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The researchers had not visited the remote island in 30 years while there were 500,000 breeding pairs. Satellite images now indicate as little as 60,000 pairs.
After three decades According to a new study, a giant colony of king penguins has lost 90% of its population.
The colony of 500,000 breeding pairs long considered the largest of the king penguins in the world, lived on Pigs Island (or less with elegance Pig Island ) a French territory in the Crozet Archipelago in the South of the Indian Ocean between South Africa and Antarctica ] [19659008] But penguins have not been counted in person since 1982, the date of the researchers' last visit. In late 2016, the researchers flew over the helicopter and saw significantly fewer penguins than expected.
Since then, by looking closely at three decades of satellite imagery, the researchers concluded that there were only 60,000 breeding pairs on the US. island . surprise for us, "said Henri Weimerskirch, a co-author on the new paper, published in Antarctic Science, and a member of the research teams in 1982 and 2016." It's really very depressing. "
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The research team suspects that climate change could play a role as it did with other penguin colonies in some parts of the Antarctic.But competition for resources, diseases and relocations may have contributed to population losses.
The researchers plan to perform a count on the island, but they They will only be able to do this by the end of autumn 2019 at the earliest, because of the costs and delays, said Dr. Weimerskirch, research director at the Chizé Center for Biological Studies. A protected nature reserve, the island Pig is not easy to reach, and the animals can not to be seen from the water, because the colony is located inland, he said. If the count of satellite images turns out to be accurate, this would significantly reduce the world population of king penguins, estimated at 1.6 million breeding pairs worldwide with this loss. They had not been considered endangered before, but could be, said Dr. Weimerskirch.
King penguins are the second largest population after emperor penguins. They do not nest, but lay an egg and parents, in turn, incubate the egg with an abdominal layer called "brood" for two months. King penguins leave their young and swim south to search for fish and squids in the waters of the Antarctic Polar Front, where cold, deep water mixes with more temperate seas. If they can not reach this polar front and can not go back in about a week, their chicks will starve.
The problem seems to have started in 1997 when an El Niño weather event caused temperatures to rise considerably year-round, pushing their food sources so far south that the chicks died before their parents could return to feed them.
All royal penguin colonies in the southern Indian Ocean suffered This year, the nearby Possession Island populations quickly rebounded According to the reports, the researchers speculated that the colony had also rebounded on the island Pig, said Dr. Weimerskirch. The satellite images show that they did not do it.
It is not known why the colony did not recover. Dr. Weimerskirch said the possibilities include some sort of infection or parasite affecting only animals on this island; predators like wildcats devastate nests; or, there may have been so much competition for resources in the giant colony that only the strongest creatures could survive.
Some of the animals may have moved from the island of Pig, about 26 square miles (about the size of Manhattan), Dr. Weimerskirch said .
He said that the team spotted a small colony on a nearby island that did not exist in the 1980s. But it only includes a few tens of thousands of breeding pairs – not as much as They have lost – and resettlement is not easy for penguins, who naturally return to where they were born
Emiliano Trucchi, an evolutionist biologist. at the University of Ferrara in Italy, who is also studying king penguins in the Crozet Archipelago, said he was troubled by the report.
The work that Dr. Trucchi and his colleagues published earlier this year raised questions about how king penguins could cope with global warming due to climate change. His model predicts that Crozet penguins will lose their habitat by 2100 and will be forced to move or die.
A local problem like what is happening on the island of Pig could accelerate their decline, says Dr. Trucchi.
"This deserves to be deepened," he said. "It's a very special process and we have to understand how to integrate that into the big picture."
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